The event happened. The only part that was never known is how many specifically were killed by the crocodiles, vs the sharks (yes there was sharks also), dehydration or their wounds.

Guns didnt help them because it was a dense swamp, up to their waist in water in places, and at the times they were attacked, pitch black, against a fast moving animal they couldnt see. On top of that they had largely abandoned their equipment before entering.